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61.
Liu Yang Pengfei Yu Wenyuan Li Fengliang Cao Xin Jin Sheng Xue Xianglong Zhang Tingwei Zhang Mingbo Wu Wenting Wu 《American Institute of Chemical Engineers》2022,68(9):e17760
Hydrogen peroxide (H2O2) has been listed as one of the 100 most important chemicals in the world. However, huge amount of residual H2O2 is hard to timely decomposed into O2 and H2O under acidic condition, easily resulting in explosion hazard. Here, we reported a core–shell structure catalyst, that is graphene with Co N structure encapsulated Co nanoparticles. Co N graphene shell serves as the active site for the H2O2 decomposition, and Co core further enhance this decomposition. Benefiting from it, the H2O2 decomposition were close to 100% after 6 cycles without pH adjustment, which increased 6 orders of magnitude compared with no catalyst. At the same time, the O2 generation reached 99.67% in 2 h with little metal leaching, and ·OH has been greatly inhibited to only 0.08%. This work can cleanly remove H2O2 with little deep oxidation and protect the process of H2O2 utilization to achieve a safer world. 相似文献
62.
Telecommunication Systems - In recent years, the widespread availability of wireless communication has stimulated research of positioning service for cellular networks. Based on the minimization of... 相似文献
63.
This paper focuses on the unconditional stability and convergence of characteristics type methods for the time-dependent incompressible MHD equations. For this purpose, we introduce a new characteristics time-discrete system. The optimal error estimates in and norms for the typical modified characteristics finite element method unconditionally can be deduced, while the whole previous works require certain time-step restrictions. Some numerical experiments document performance of the characteristics type methods for the time-dependent incompressible MHD equations. 相似文献
64.
65.
Recently, many researchers have concentrated on distant supervision relation extraction (DSRE). DSRE has solved the problem of the lack of data for supervised learning, however, the data automatically labeled by DSRE has a serious problem, which is class imbalance. The data from the majority class obviously dominates the dataset, in this case, most neural network classifiers will have a strong bias towards the majority class, so they cannot correctly classify the minority class. Studies have shown that the degree of separability between classes greatly determines the performance of imbalanced data. Therefore, in this paper we propose a novel model, which combines class-to-class separability and cost-sensitive learning to adjust the maximum reachable cost of misclassification, thus improving the performance of imbalanced data sets under distant supervision. Experiments have shown that our method is more effective for DSRE than baseline methods. 相似文献
66.
探究了GB/T 3965—2012《熔敷金属中扩散氢测定方法》中载气热提取法收集条件对测定扩散氢含量的影响,并与水银法进行了对比。研究结果表明,样本炉温设定为400℃,A型试块的内部温度大约在51 min时稳定在358℃左右,B型试块内部温度大约在27 min时稳定在391℃左右;载气热提取法电信号曲线收集结束点的电信号及斜率均接近0时获得的结果与水银法具有较好的一致性。 相似文献
67.
针对人脸识别系统中出现的通过照片或视频“欺诈”解锁问题,提出一种活体检测方法,通过随机指令判断被检测对象是否为真人。利用HOG特征和随机森林算法对摄像头采集的图像进行人脸检测,预测脸部68个特征点位置,把68个特征点位置和脸部位置的相对位置归一化后作为姿态的特征,提取的姿态特征与SVM分类器相结合,训练出分类效果较好的头部姿态估计分类器。通过多次实验,对特征提取方法进行优化,进一步提高检测准确率。最后,使用随机互动式命令序列对被检测人发出指令,实现活体检测。该方法对头部姿态估计具有较高的鲁棒性,并且可以有效地防范照片和视频认证攻击。 相似文献
68.
69.
LeSheng Jin 《国际智能系统杂志》2019,34(6):1206-1222
Hesitance is an innate human psychological phenomenon pervasive in our daily life. Although it is very complex and still not fully understood, there have been many studies related to this interesting topic. In this study, we proposed two fundamental problems about hesitance: the first is the generating problem, which is related to how to elicit hesitance information from human thinking; the second is the measuring problem, which is related to how to devise effective and reasonable methods to measure hesitance degrees from given hesitance information. With these two fundamental questions, we first discussed and analyzed several examples in real life involving hesitance, showing that it can indeed be recorded and represented. Then we roughly classified the hesitance information into two major classes: static hesitance and dynamic hesitance. Some simple and interesting methods were proposed to elicit hesitance, and more reasonable methods were proposed to measure the hesitance degree from the two classes of hesitance information. All methods that have been discussed in this study try to avoid complexity in every aspect while reserving strictness and reasonability; therefore, the present study provides suitable information for practitioners with different backgrounds. 相似文献
70.
Ting Hui Yuan Zhen Hua Zhang Jin Li Da Quan Zhang Li Xin Gao Wen Ge Li Zhi Feng Fan 《工业材料与腐蚀》2019,70(7):1298-1305
In the study, polyaniline/reduced‐graphene oxide (PANI‐RGO) composites, fabricated by loading 2, 5, and 8wt% graphene oxide, was prepared by in‐situ emulsion polymerization and reduction. They are characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. Epoxy coatings adding PANI and PANI‐RGO composites were coated on the surface of AA5083 Al alloy. The anticorrosion performance of the coatings is measured by electrochemical impedance spectroscopy and potentiodynamic polarization curve in 3.5wt% NaCl solution. The results demonstrate that the epoxy/PANI‐RGO coating exhibits a better protection against AA5083 alloy corrosion compared with the epoxy/PANI coating. Enhancement of the passivation performance of PANI was obtained by the addition of RGO into epoxy/PANI coating system. 相似文献